Advanced Distillation Technologies

Preface xiii Acknowledgements xv 1 Basic Concepts in Distillation 1 1.1 Introduction 1 1.2 Physical Property Methods 2 1.3 Vapor Pressure 6 1.4 Vapor-Liquid Equilibrium and VLE Non-ideality 8 1.4.1 Vapor-Liquid Equilibrium 8 1.4.2 VLE Non-ideality 11 1.5 Relative Volatility 13 1.6 Bubble Point Calculations 14 1.7 Ternary Diagrams and Residue Curve Maps 16 1.7.1 Ternary Diagrams 16 1.7.2 Residue Curve Maps 18 1.8 Analysis of Distillation Columns 24 1.8.1 Degrees of Freedom Analysis 26 1.8.2 McCabe-Thiele Method 27 1.8.3 Approximate Multicomponent Methods 33 1.9 Concluding Remarks 34 References 35 2 Design, Control and Economics of Distillation 37 2.1 Introduction 37 2.2 Design Principles 38 2.2.1 Operating Pressure 39 2.2.2 Heuristic Optimization 40 2.2.3 Rigorous Optimization 41 2.2.4 Feed Preheating 42 2.2.5 Intermediate Reboilers and Condensers 42 2.2.6 Heat Integration 43 2.3 Basics of Distillation Control 44 2.3.1 Single-End Control 46 2.3.2 Dual-End Control 49 2.3.3 Alternative Control Structures 52 2.3.4 Constraint Control 53 2.3.5 Multivariable Control 54 2.4 Economic Evaluation 55 2.4.1 Equipment Sizing 56 2.4.2 Equipment Cost 59 2.4.3 Utilities and Energy Cost 62 2.4.4 Cost of Chemicals 63 2.5 Concluding Remarks 63 References 64 3 Dividing-Wall Column 67 3.1 Introduction 67 3.2 DWC Configurations 70 3.3 Design of DWCs 75 3.3.1 Heuristic Rules for DWC Design 77 3.3.2 Approximate Design Methods 78 3.3.3 Vmin Diagram Method 79 3.3.4 Optimal Design of a DWC 82 3.4 Modeling of a DWC 83 3.4.1 Pump-Around Model 84 3.4.2 Two Columns Sequence Model 84 3.4.3 Four Columns Sequence Model 85 3.4.4 Simultaneous Models 86 3.4.5 Simulation of a Four-Product DWC 86 3.4.6 Optimization Methods 86 3.5 DWC Equipment 87 3.5.1 Liquid/Reflux Splitter 89 3.5.2 Column Internals 91 3.5.3 Equipment Sizing 91 3.5.4 Constructional Aspects 94 3.6 Case Study: Separation of Aromatics 97 3.7 Concluding Remarks 103 References 107 4 Optimal Operation and Control of DWC 111 4.1 Introduction 111 4.2 Degrees of Freedom Analysis 112 4.3 Optimal Operation and Vmin Diagram 114 4.4 Overview of DWC Control Structures 117 4.4.1 Three-Point Control Structure 118 4.4.2 Three-Point Control Structure with Alternative Pairing 120 4.4.3 Four-Point Control Structure 121 4.4.4 Three-Point Control Structure with Nested Loops 121 4.4.5 Performance Control of Prefractionator Sub-system using the Liquid Split 122 4.4.6 Control Structures Based on Inferential Temperature Measurements 123 4.4.7 Feedforward Control to Reject Frequent Measurable Disturbances 126 4.4.8 Advanced Control Techniques 127 4.5 Control Guidelines and Rules 128 4.6 Case Study: Pentane-Hexane-Heptane Separation 129 4.7 Case Study: Energy Efficient Control of a BTX DWC 132 4.7.1 Energy Efficient Control Strategies 135 4.7.2 Dynamic Simulations 139 4.8 Concluding Remarks 148 References 149 5 Advanced Control Strategies for DWC 153 5.1 Introduction 153 5.2 Overview of Previous Work 154 5.3 Dynamic Model of a DWC 156 5.4 Conventional versus Advanced Control Strategies 163 5.4.1 PID Loops within a Multi-loop Framework 163 5.4.2 Linear Quadratic Gaussian Control 165 5.4.3 Generic Model Control 167 5.4.4 Multivariable Controller Synthesis 167 5.5 Energy Efficient Control Strategies 171 5.5.1 Background of Model Predictive Control 173 5.5.2 Controller Tuning Parameters 175 5.5.3 Dynamic Simulations 176 5.6 Concluding Remarks 180 Notation 181 References 183 6 Applications of Dividing-Wall Columns 187 6.1 Introduction 187 6.2 Separation of Ternary and Multicomponent Mixtures 188 6.3 Reactive Dividing-Wall Column 195 6.4 Azeotropic Dividing-Wall Column 198 6.5 Extractive Dividing-Wall Column 199 6.6 Revamping of Conventional Columns to DWC 203 6.7 Case Study: Dimethyl Ether Synthesis by R-DWC 205 6.8 Case Study: Bioethanol Dehydration by A-DWC and E-DWC 212 6.9 Concluding Remarks 223 References 223 7 Heat Pump Assisted Distillation 229 7.1 Introduction 229 7.2 Working Principle 231 7.3 Vapor (Re)compression 232 7.3.1 Vapor Compression 233 7.3.2 Mechanical Vapor Recompression 233 7.3.3 Thermal Vapor Recompression 234 7.4 Absorption-Resorption Heat Pumps 234 7.4.1 Absorption Heat Pump 234 7.4.2 Compression-Resorption Heat Pump 235 7.5 Thermo-acoustic Heat Pump 236 7.6 Other Heat Pumps 240 7.6.1 Stirling Cycle 240 7.6.2 Vuilleumier Cycle 241 7.6.3 Brayton Cycle 241 7.6.4 Malone Cycle 242 7.6.5 Solid-Sorption Cycle 242 7.7 Heat-Integrated Distillation Column 244 7.8 Technology Selection Scheme 245 7.8.1 Energy Efficient Distillation Technologies 246 7.8.2 Multicomponent Separations 249 7.8.3 Binary Distillation 254 7.8.4 Selected Scheme Applications 263 7.9 Concluding Remarks 265 References 265 8 Heat-Integrated Distillation Column 271 8.1 Introduction 271 8.2 Working Principle 273 8.3 Thermodynamic Analysis 277 8.4 Potential Energy Savings 280 8.4.1Partial Heat Integrated Distillation Column (p-HIDiC) 280 8.4.2 Ideal Heat Integrated Distillation Column (i-HIDiC) 281 8.5 Design and Construction Options 282 8.5.1 Inter-coupled Distillation Columns 284 8.5.2 Distillation Column with Partition Wall 285 8.5.3 Concentric Distillation Column 287 8.5.4 Concentric Column with Heat Panels 288 8.5.5 Shell & Tube Heat-Exchanger Column 289 8.5.6 Plate-Fin Heat-Exchanger Column 290 8.5.7 Heat Transfer Means 292 8.6 Modeling and Simulation 295 8.7 Process Dynamics, Control, and Operation 297 8.8 Applications of HIDiC 300 8.9 Concluding Remarks 304 References 305 9 Cyclic Distillation 311 9.1 Introduction 311 9.2 Overview of Cyclic Distillation Processes 313 9.3 Process Description 316 9.4 Mathematical and Hydrodynamic Model 319 9.4.1 Mathematical Model 319 9.4.2 Hydrodynamic Model 321 9.4.3 Sensitivity Analysis 323 9.5 Modeling and Design of Cyclic Distillation 327 9.5.1 Modeling Approach 329 9.5.2 Comparison with Classic Distillation 331 9.5.3 Design Methodology 331 9.5.4 Demonstration of the Design Procedure 333 9.6 Control of Cyclic Distillation 335 9.7 Cyclic Distillation Case Studies 338 9.7.1 Ethanol-Water Stripping and Concentration 338 9.7.2 Methanol-Water Separation 341 9.8 Concluding Remarks 347 References 349 10 Reactive Distillation 353 10.1 Introduction 353 10.2 Principles of Reactive Distillation 354 10.3 Design, Control and Applications 357 10.4 Modeling Reactive Distillation 362 10.5 Feasibility and Technical Evaluation 364 10.5.1 Feasibility Evaluation 364 10.5.2 Technical Evaluation 367 10.6 Case Study: Advanced Control of a Reactive Distillation Column 371 10.6.1 Mathematical Model 371 10.6.2 Open-Loop Dynamic Analysis 374 10.6.3 Closed-Loop Performance 374 10.7 Case Study: Biodiesel Production by Heat-Integrated RD 378 10.8 Case Study: Fatty Esters Synthesis by Dual RD 383 10.9 Concluding Remarks 387 References 388 Index 393